Terms of Reference

Review of the Framework and Assessment for 4VWX Silver Hake

Regional Peer Review – Maritimes Region

Part 1 - Data Inputs: May 30-31, 2012 (Dartmouth, NS)
Part 2 - Modelling: November 14-15, 2012 (Dartmouth, NS)
Part 3 - Assessment: December 11, 2012 (Dartmouth, NS) [ ¹ ]

Chairperson: Tana Worcester

Context

Silver hake is a bottom dwelling member of the gadoid family, found from Cape Hatteras to the Grand Banks and Gulf of St. Lawrence. A population of silver hake occurs on the Scotian Shelf (Div. 4VWX). The last assessment of the status of Scotian Shelf silver hake was conducted in 2009 (DFO 2010). A new assessment has been requested by DFO Resource Management to provide harvest advice in support of the fishery in the Maritimes Region. DFO Science has been asked to review and evaluate the biological and fishery information on 4VWX silver hake status and characterize the uncertainty of the results; specifically, provide information on distribution, biomass estimates, length and age composition, condition, highlighting any trends over the long-term (length of assessment), mid-term (past 15 years), and most recent period (5 years). Given known problems with the assessment model for this stock (as described in the 2009 assessment), it was determined that a new framework was required. The review of the framework and assessment for 4VWX will be conducted in three parts: review of data inputs, review of the model, and then the assessment.

Objectives

Part 1 – Data Inputs

• Describe the basis of the management unit
  
  
• Review fisheries and survey data sources, including
  • Fishery sampling: commercial catch, distribution, length and age composition
  • DFO Research Vessel (RV) survey sampling: survey catch, distribution, length and age composition, condition
  • Industry (ITQ) survey sampling: survey catch, distribution
    
    
• Review catch-at-age, including
  • Documentation of past aging approach
  • New aging approach using otolith weights
    
    
• Review relevant biological and ecological information, including
  • Biology: growth, age, life history, sex, fecundity, natural mortality, spawning location and timing, recruitment
  • Ecosystem information: bycatch, trophic information, temperature, fishery footprint
    
    
• Review indices of abundance, including
  • RV survey indices
  • ITQ survey indices
  • CPUE index

Part 2 – Modelling Review

• Determine the methodology to estimate the current state of the stock, including methods for estimating stock size and fishing mortality
  
  
• Determine the methodology to characterize stock productivity including reference points for fishing mortality and spawning stock biomass
  
  
• Determine forecasting methodology for providing advice on harvest levels
  
  
• Provide guidance on inter-framework review activities, including
  • Review procedure and frequency of providing fisheries management advice
  • Review events that would trigger an earlier-than-scheduled assessment

Part 3 – Assessment

• Report on the current status of 4VWX silver hake based on the latest information from fisheries and research surveys, and characterize the uncertainty of results. Specifically, provide information on distribution, biomass estimates, length and age composition, and condition, highlighting any trends over the long-term (length of assessment), mid-term (past 15 years), and most recent period (5 years).
  
  
• Evaluate the potential consequences of different harvest levels during the 2013/2014 fishery on stock abundance and exploitation rate.
  
  
• Identify appropriate reference points for 4VWX silver hake and evaluate the current status in relation to these reference points.

Expected Publications

• Science Advisory Report
• Proceedings
• Research Document(s)

Participation

• DFO Science and Resource Management 
• Provincial representatives
• Fishing industry  
• Aboriginal communities/organizations
• Other invited experts  

References

DFO. 2010. Silver Hake on the Scotian Shelf (Divisions 4VWX). DFO. Can. Sci. Advis. Sec. Sci. Advis. Rep. 2010/007.

¹ December 7, 2012: meeting date updated to December 11 for Part 3.